In this file go to the "StepOptions" -> "Deploy Kubernetes Applications" -> "helmCharts" section and add a new JSON property (highlighted below in red) with the name of the helm chart you chose in section Adding helm charts (marked in green).
For each of your agents add the three lines for the agent's image repository and tag. Make sure that the deployment and container names (marked in yellow) do match the ones you chose in Deployments/PODs/Containers/Volumemounts.

You can use the following snippet as a blueprint.